Typescript demonstrates that you can have a fully dynamic language but also provide a type system which can support as much (or as little) type checking as is appropriate or desired.

I can take my chances in Typescript by just using 'any' everywhere but if I do want to constrain variables to particular types, the compiler will fully support me and provide guarantees about the restrictions I've specified via the type signatures.

It sounds exactly the same as Python with pyright or mypy. A novel approach is taken by Elixir, which actually makes sure the compile time types match runtime types. That is , you can't call a function with an incorrect input type at runtime https://elixir-lang.org/blog/2023/09/20/strong-arrows-gradua...